THE MASTER 71 It was in those early times of complete responsibility of the master that use of bottomry bonds and respondentia bonds was regularly made. When a master of a ship found that the freight he had earned and collected, and other ' moneys on board were insufficient to pay for charges he had incurred, then bottomry bonds were used, by which the ship j was pledged against a loan. If the ship proved to be in- sufficient for this purpose then the cargo was also pledged by way of respondentia bonds. Now, however, within a few minutes large sums of money may be transmitted from one country to another, and the need for these documents has consequently decreased. Apart from the powers of managing the ship's business, the master has supreme power on board his ship, and may arrest either the crew or passengers of the ship if they be- come a menace to the vessel. In the case of a passenger being arrested it is usual for him or her to be detained in a cabin until the vessel reaches its destination. In the event of a person becoming a dangerous menace, then the master may have such a person put in irons. In all cases prisoners are handed over to the authorities at the port of destination, or if convenient at an intermediate port. In the case of a mutiny, any act of the master is regarded as one of self-defence, and he may call on all persons on board to render assistance (in a similar manner to police officers on land who may demand assistance in a time of danger from any person), failure to give such assistance constituting a crime. A master has full authority to purchase necessary stores and equipment for his ship, and t^e charges for same are a charge against the owners, but goods which may be deemed unnecessary, although ordered by the master for the owners, may be chargeable to the master. He is only allowed to make purchases which are necessary and reasonable. What is "a necessary" may be ascertained by determining whether the owner, being a prudent man, would have acted in a simfar manner had he been on board at the time.